The present invention relates to an imaging apparatus and an imaging method using beam irradiation sources such as laser beam sources, and preferably to an apparatus and its method for generating a change in an imaging characteristic (physical change) such as projections and depressions or a change in solubility to solvent on an imaging medium such as an imaging film, an imaging plate according to imaging data using a beam digitally controlled. Also, the present invention relates to an optical fiber array apparatus and an imaging head apparatus, which are used in the above imaging apparatus. Moreover, the present invention relates to a printing apparatus using the above imaging apparatus.
FIG. 61 shows an example of an imaging apparatus using beam irradiation sources such as laser beam source. As described in Unexamined Japanese Patent Publication No. 6-186750 (corresponding to U.S. Pat. No. 5,339,737), an imaging apparatus 9 comprises a medium support drum 91 for winding an imaging medium around on its outer surface, an imaging head 92 including beam irradiation sources and an optical system for condensing beams from the beam irradiation sources, a beam irradiation source control unit 96, and a cable 95 for connecting the imaging head 92 to the beam irradiation source control unit 96. Moreover, the imaging head 92 is fixed onto a linear stage 94 for realizing a parallel movement with respect to an axial direction of the medium support drum 91.
As the linear stage 94, a linear motor typed linear stage, which is directly driven by a linear motor, and a ball screw typed linear stage using a ball screw typed linear guide are generally used. The distance between the imaging head 92 and the imaging medium 98 is adjusted such that the beams are condensed on the surface of the imaging medium. The outputs of the beam irradiation sources are controlled enough to generate a change in an imaging characteristic (physical change) such as projections and depressions according to imaging data or a change in solubility to solvent between a beam irradiation section of the imaging medium 98 and a non-irradiation section.
In executing the imaging, the beam irradiation sources are switched to correspond to imaging data as performing the following operations. Specifically, the medium support drum 91 around which the imaging medium 98 is wound is rotated in a direction of an arrow R of the figure using a motor 93 such as a pulse motor. Also, the imaging head 92 fixed onto the linear stage 94 is moved in a direction of an arrow S of the figure to be parallel to the shaft of the medium support drum. This generates a two-dimensional change in an imaging characteristic (physical change), such as physical projections and depressions according to imaging data or a change in solubility to solvent, on the surface of the imaging medium.
Generally, a direction R of lines imaged by the rotation of the medium support drum 91 is defined as a main scanning direction, and a direction S of lines imaged by the parallel movement of the imaging head 92 is defined as a sub-scanning direction.
As the method for improving the performance of such the imaging apparatus, there can be easily considered the plurality of beam irradiation sources, which can be independently driven.
The improvement of the performance of the imaging apparatus means to enhance the imaging speed and resolution. The relationship of tradeoff is established between the imaging speed and the resolution. In this case, the resolution denotes that how many dots can be formed per unit length, and dpi (dots per inch) is generally used as a unit.
For example, 2540 dpi corresponds to 100 dots/mm. As one example, suppose that the imaging head having i beam irradiation sources is used to execute imaging i lines continuous to the main scanning direction simultaneously by i beam irradiation sources. At this time, a dot distance dp for realizing a predetermined resolution r is 1/r. Then, when the linear motor typed linear stage is used, in many cases, the imaging head is moved by a predetermined distance after the imaging corresponding to one circumference in the main scanning direction is finished. When the ball screw typed linear stage is used, the imaging head is moved by a predetermined distance during one turn of the medium support drum. The predetermined distance is i times as large as the dot distance dp on the imaging medium.
Thereafter, next i lines are imaged, and these series of operations are repeated, and the imaging of the entire surface of the imaging area is completed. By use of i beam irradiation sources, the time required for imaging is reduced to 1/i when the resolution is the same.
In order to increase the resolution j times, it is needed that the dot distance be set to dp/j and that the distance of the movement of the imaging head be set to dpxc3x97i/j. Then, time required for imaging results in j/i times.
As one of the methods using the plurality of beam irradiation sources, a laser diode array is used. The general outline view is shown in FIG. 39.
A laser diode array 8 includes eight laser diodes, which can be independently driven, in one chip. The laser diodes have laser beam emission ends 81a to 81h, drive side electrodes 82a to 82h, and a rear face common electrode 83 for all laser diodes, respectively. The flow of a predetermined current to the drive side electrodes 82a to 82h allows the laser beam to be emitted from the corresponding laser beam emission ends 81a to 81h. In this case, the predetermined current means a current value of more than a threshold value at which the laser diode starts the laser oscillation.
As another method using the plurality of beam irradiation sources, the fiber array is used. The outline view of a fiber output laser apparatus is shown in FIG. 42.
A laser apparatus 6 comprises a laser diode chip having at least one light emission end, a conductive member for realizing the electrical contact between an electrode of the diode chip and an outer unit, a package section 61 having a heat conduction member for escaping heat from the diode chip to the outside and an optical system for making the laser beams incident onto the optical fibers from the laser diode, and an optical fiber 62 for guiding laser beams to the outer unit.
Then, the laser beam is emitted from an emission end 63 of the optical fiber 62. As shown in FIG. 58, the emission end 63 of the optical fiber 62 has a core portion 64 and a clad portion 65, and the laser beam is output from the core portion 64. Then, the emission ends 63 of the plurality of fibers of the laser device of the plurality of fiber outputs are arranged in an array form and fixed, thereby structuring the fiber array. When the fiber array is used as the beam irradiation sources, the maximum distance between the beam irradiation sources is restricted by an outside dimension of the clad portion 65.
In many cases, it is impossible to arrange the beam irradiation sources, that is, the respective emission ends, to be close to each other without any space in either of the methods of the laser diode array and the fiber array. In order to perform the imaging in the imaging area of the imaging medium without any space, the array must be inclined to the sub-scanning direction S by a predetermined angle xcex8 as shown in FIG. 6. An array 7 comprises eight beam irradiation sources 71a to 71h, and its inclination angle xcex8 is defined by the following equation (1).
cos xcex8=ds/asxe2x80x83xe2x80x83(1)
where as is a distance between the beam irradiation sources, a light source surface dot distance ds obtained by converting the central distance between dots, which should be formed to obtain a predetermined resolution in the sub-scanning direction S, to the dimension at the beam irradiation source surface, and the medium surface dot distance dp is divided by a magnification of the optical system.
For example, dp=10 xcexcm when resolution is 2540 dpi, and ds=40 xcexcm when the magnification of the optical system is xc2xc. At this time, the beam diameter is larger than the dot distance dp, preferably about {square root over (2)} times in order to make it possible completely image the entire surface of the imaging area.
Moreover, in this type of imaging apparatus, Unexamined Japanese Patent Publication No. 5-16320 is known as one of the methods for improving the response of the laser beam sources so as to accelerate the imaging speed. In this method, at an imaging data absent time, a current is made to flow to a value close to a threshold value at which the laser beam sources actuate. Then, in the laser beam sources, time required for switching an imaging data absent state to an imaging data present is reduced.
FIG. 50 shows one example of a characteristic of current-optical output in the laser diode. As shown in the figure, a current value at which the optical output is started to rise is a threshold current Ith, and a current value at which the imaging is actually executed is an operation current Ion. At this time, an optical output Pon emitted from the laser beam source is an output enough to generate a change in an imaging characteristic between the laser beam irradiation section of the imaging medium and the no-irradiation section thereof. FIG. 62 shows a control signal to be transmitted to a laser diode from a laser beam source driving circuit in the laser beam source control unit, a current value flowing to the laser diode, and a change in the optical output emitted from the laser beam source, respectively, at an imaging operation time.
Unexamined Japanese Patent Publication No. 5-16320 discloses a method for changing the current value at the imaging data absent time to an extent of the threshold current of the semiconductor laser. In the specification of the above publication, there is a description in which the semiconductor laser beam may be generated if the extent of laser power such that no depression is formed in a plate at the imaging data absent time. However, the above specification does not describe the specific numeral value of what extent of the range is allowable.
FIGS. 63A and 63B show examples of a method for manufacturing an optical fiber array used in the above-mentioned imaging apparatus. As shown in FIG. 63A, a V-shape groove corresponding to the number of optical fibers is formed in an optical fiber support member 3012 so that the optical fibers are arranged in the V-shaped groove. Then, the optical fibers are pressed from the upper portion by a pressing member 3013, and a space between the optical fibers is filled with adhesive to be hardened and combined as one unit. In FIG. 63B, a fixed groove whose width corresponds to the number of optical fibers is formed in the optical fiber support member 3012 so that the optical fibers are arranged in the fixed groove. Then, the optical fibers are pressed from the upper portion by the pressing member 3013, and a space between the optical fibers is filled with adhesive to be hardened and combined as one unit.
According to the inventors"" knowledge of the present invention, contrivance is added to sub-scanning means of this type of the optical fiber apparatus, and image data is rearranged. Thereby, the optical fiber apparatus can be arranged in a direction parallel to the sub-scanning direction as in FIG. 64A without being inclined at a predetermined angle as shown in FIG. 64B.
In this case, contrivance to be added to the sub-scanning means denotes as follows. Specifically, when the number of optical fiber emission ends is n, a dot distance necessary for obtaining a predetermined resolution is dp, and a distance between the emission ends projected onto the imaging medium is ap, a magnification 1/h of the optical system is adjusted to establish the relationship ap=hdp and the feeding of the sub-scanning means the repetition of the feeding of dp of (hxe2x88x921) times and one feeding of {napxe2x88x92(hxe2x88x921)dp}.
For realizing such an irregular delivery, it is desirable that the linear motor drive stage be used. The rearrangement of data means a process for adjusting the case in which lines discontinuous to the sub-scanning direction are imaged simultaneously in executing the above-mentioned feeding of the sub-scanning. The manufacturing method of the optical fiber array apparatus in this case is the same as the above-mentioned method, that is, an angle may be changed when the optical fiber array apparatus may be incorporated into the imaging head.
In the imaging head apparatus using the laser beam sources of the optical fiber array type in which all optical fiber emission ends are arranged in a straight line, it is required that all laser beams be satisfactorily condensed on the imaging medium.
In this case, however, a good image area of the optical system, which is used to cover all optical fiber emission ends on both edges, must be enlarged with an increase in the number of the optical fiber emission ends. For this reason, the manufacturing cost of the optical system and its size are increased. When the laser beam sources are inclined to the sub-scanning direction S, timing for imaging the dots at the same position in the main scanning direction is largely shifted in the optical fiber emission ends on both edges. In order to justify the position of the dots in the main scanning direction formed by the above imaging head apparatus, the shift amount must be counted in a manner of an electric circuit. For this reason, the electric circuit for controlling timing of the imaging becomes complicated or expensive with an increase in the number of the optical fiber emission ends to be arranged in a straight line.
In order to solve such a problem, it is considered that the optical fiber emission ends are arrayed in a plurality of rows (optical fiber multiple row). FIGS. 65A and 65B show examples of the array method of the optical fiber emission ends. FIG. 65A is a two-row array like a barrel piling, and FIG. 65B is a three-row array of vertical piling.
The two-row array like a barrel piling is that a second optical fiber array is arranged on a first optical fiber array such that the pitch of the emission ends becomes the same as the first optical fiber row. In this case, the first optical fiber row is formed such that the emission ends of the optical fibers are arrayed with a predetermined pitch. The two-row array like a barrel piling is formed such that the shift in the array direction between the first optical fiber row and the second optical fiber row becomes 0.5 times as large as the predetermined pitch. According to the above array, the convex portions of the other optical fiber row enter the concave portions of one optical fiber row, which are formed since the optical fibers are substantially columnar shape. Thereby, both fiber rows are closely contacted to each other. In the array of vertical piling, there is no shift of the optical fiber rows. In these array methods, the manufacturing method of the optical fiber array is basically the same as the above-mentioned method.
In the case of the two-row array like a barrel piling shown in FIG. 66A, an optical fiber fixed groove, having a width corresponding to the size which is one larger than the number of optical fibers, is formed in the optical fiber support member 3012. Then, the optical fiber row of the first stage and a dummy fiber 3014 are arranged in the fixed groove. Then, the optical fiber row of the second stage is arranged thereon, and pressed from the upper portion by the pressing member 3013, and the space therebetween is filled with adhesive to be hardened and combined as one unit.
In the case of the three-row array of vertical piling of FIG. 66B, an optical fiber fixed groove, having a width corresponding to the number of optical fibers, is formed in the optical fiber support member 3012. Then, the optical fiber row of the first stage is arranged in the fixed groove. Then, the optical fiber of the second stage is arranged thereon through a spacer 3018, and the optical fiber of the third stage is arranged thereon through the space 3018 again. Finally, the optical fibers are pressed from the upper portion by the pressing member 3013, and the space therebetween is filled with adhesive to be hardened and combined as one unit.
The dummy fiber 3014 in the two-row array like a barrel piling and the spacer 3018 in the three-row array of vertical piling are used to stabilize the position of the fibers.
However, in the conventional imaging apparatus using the imaging head in which the plurality of the beam irradiation sources are arranged in an array form, the following problems are present. More specifically, when at least one of the beam irradiation sources is out of order, the apparatus cannot be completely operated until the entire array or the entire imaging head is repaired or replaced. Moreover, when the plurality of beam irradiation sources is formed in the same semiconductor chip at the time of manufacturing the imaging head, all beam irradiation sources become defective if at least one of the beam irradiation sources becomes defective because of local defectiveness in the semiconductor chip. This reduces yield of the imaging head. When the number of beam irradiation sources per one imaging head is increased to improve the performance of the imaging apparatus, the above-mentioned problems become more conspicuous.
When all beam irradiation apparatus are arranged in a straight line, the good image area of the optical system, which is used to cover all optical fiber emission ends on both edges, must be enlarged in order to condense all beams on the imaging medium in accordance with an increase in the number of the optical fiber emission ends. For this reason, there is a problem in which the cost of the optical system and its size are increased. Since the laser beam sources are simultaneously inclined to the sub-scanning direction S, timing for imaging the dots at the same position in the main scanning direction is largely shifted in the optical fiber emission ends on both edges. In order to justify the position of the dots in the main scanning direction formed by the above imaging head apparatus, the shift amount must be counted in a manner of an electric circuit. For this reason, the electric circuit for controlling timing of the imaging becomes complicated or expensive in accordance with an increase in the number of the optical fiber emission ends to be arranged in a straight line.
In the conventional imaging apparatus in which the current is made to flow to the value close to the threshold value at which the laser beam sources actuate at the imaging data absent time in order to improve the response of the laser beam sources and accelerate the imaging speed, the following problem exists. More specifically, the threshold current value Ith at which the laser beam sources actuate is considerably smaller than the operation current Ion for obtaining outputs enough to generate a change in the imaging characteristic (physical change) such as a change in the physical shape of the imaging medium or a change in solubility to solvent. For this reason, there is a problem in which a reduction in switching time is not largely expected.
As described in Unexamined Japanese Patent Publication No. 5-16320, if a large current value is set to obtain such exposure energy that does not reach sensitivity of the imaging medium even at the imaging data absent time, it can be considered that large improvement can be obtained. However, when the adjacent lines in the main scanning direction are simultaneously imaged using the plurality of laser beam sources according to this method, the following problem may occur. More specifically, at the imaging data present time, it is assumed that exposure energy is set to a value, which is fairly close to the sensitivity of the imaging medium. In this case, there is a possibility that the closest line will be erroneously imaged even in the imaging data absent portion because of the overlap of the irradiation areas of the adjacent laser beam sources.
Also, in the conventional imaging apparatus, the distance between the imaging head including the laser beam sources and the imaging medium must be delicately adjusted. It takes much time to condense the beams on the surface of the imaging medium satisfactorily so as to execute a good imaging. The actual adjustment is a trial-and-error work. Specifically, the imaging result is observed by a magnifying glass, the distance is adjusted by focal adjusting means based on the observation result, and the imaging is executed again. Moreover, the determination cannot be made only by the imaging result, depending on the imaging medium. The estimation can be often performed only after the imaging medium is used as a press plate and the printing is executed. In this case, the imaging post-process and the printing process are further needed. Moreover, the cost and time are required. Even when the thickness of the imaging medium is changed, it is needed that the distance between the imaging head and the imaging medium be adjusted again. In many cases, it is impossible to image a plurality of kinds of imaging mediums having a different thickness by one imaging apparatus since the complicated adjustment work of the distance between the imaging head and the imaging medium must be frequently executed.
In the conventional multi-stage piling array of the optical fibers, the following problem exists.
More specifically, in the two-row array like a barrel piling shown in FIG. 65A, the optical axis of the optical fibers on the second stage (upper stage) in the sub-scanning direction is positioned at just the center of the optical axis of the optical fibers on the first stage (lower stage). As a result, resolution, which is twice as high as the horizontal array of one row, can be obtained. However, in order to execute the imaging in the imaging area of the imaging medium without having any space, the clad diameter must be reduced to a value close to a core diameter. Or, imaging data must be rearranged after adding contrivance to the sub-scanning method as mentioned above. Moreover, in piling the optical fibers on the third stage like a barrel piling manner, since the position of the optical axis of the optical fibers in the sub-scanning direction is coincident with the first stage, the multi-stage piling effect will be lost.
In the array of vertical piling shown in FIG. 65B, the optical fiber array must be inclined at a predetermined angle such that the projection distance between the optical fiber arrays to the sub-scanning direction is constantly maintained. However, the shift amount of each optical array in the sub-scanning direction is defined by only the inclination angle, and the shift of each stage can be neither defined and nor adjusted individually. Therefore, it is difficult to manufacture the optical fiber array having an excellent positional accuracy.
An object of the present invention is to provide an imaging apparatus, which can execute an alternative operation without completely disabling the apparatus when a part of a plurality of beam-irradiation sources is out of order.
Another object of the present invention is that even when a part of the beam irradiation sources becomes defective because of local defectiveness in the semiconductor chip in the case of forming a plurality of beam irradiation sources in the same semiconductor chip at the time of manufacturing an imaging head, the imaging apparatus can be used with limitations and a considerable reduction in yield can be prevented.
Another object of the present invention is to provide an imaging apparatus having an imaging head having many beam irradiation sources arranged without increasing the cost of an optical system and its size and without complicating an electric circuit for controlling timing of imaging or increasing the manufacturing cost thereof.
Another object of the present invention is to provide an imaging apparatus which can largely reduce time required for changing from an imaging data absent state of the beam irradiation sources to an imaging data present state so as to make it possible to improve imaging speed, and to provide an imaging method in the imaging apparatus for executing imaging using a plurality of beam irradiation sources which can be independently driven.
Another object of the present invention is to provide an imaging apparatus and an imaging method, which does not easily generate an erroneous imaging at an imaging data absent portion caused by setting exposure energy to a value, which is fairly close to the sensitivity of the imaging medium, because of the overlap of irradiation areas of the adjacent laser beam sources.
Another object of the present invention is to provide an imaging apparatus, which can easily execute the adjustment of the distance between an imaging head and an imaging medium.
Another object of the present invention is to provide a multi-stage piling optical fiber array apparatus having an excellent positional accuracy, an imaging head apparatus using such an optical fiber array apparatus, and an imaging apparatus for executing imaging by the imaging head apparatus.
Another object of the present invention is to provide a printing apparatus for executing printing onto a recording medium using an imaging medium imaged by the above imaging apparatus.
In order to attain the above object, according to the present invention, there is provided an imaging apparatus having a plurality of beam irradiation sources which can be individually driven, said imaging apparatus comprising: n (n=2 or more integer) light source blocks including k (k=2 or more integer) beam irradiation sources; and one or more and below n beam irradiation source driving devices connectable for each block.
According to another embodiment of the present invention, there is provided an imaging apparatus having a plurality of beam irradiation sources which can be individually driven, said imaging apparatus comprising: supporting means for an imaging medium; n (n=2 or more integer) light source blocks including k (k=2 or more integer) beam irradiation sources; at least one or more and below n beam irradiation source driving devices connectable for each block; and scanning means, provided between said light source blocks and said supporting means in a sub-scanning direction, capable of changing a feed amount.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein said respective light source blocks including a plurality of beam irradiation sources arranged in a line.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein said blocks are arranged in the same direction as the direction where the beam irradiation sources of the blocks are arranged.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein said blocks are arranged to have a predetermined angle to the direction where the beam irradiation sources of the blocks are arranged.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein said imaging apparatus including an imaging head manufactured using the light source blocks having at least one of the beam irradiation sources of said blocks is normally operated and at least one of the beam irradiation sources is abnormally operated.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein said beam irradiation sources are emission ends of a laser device formed of a compound semiconductor.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein the beam irradiation sources of one block are formed in the same semiconductor chip.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein all beam irradiation sources are formed in the same semiconductor chip.
According to a favorable embodiment of the present invention, there is provided the imaging apparatus wherein said beam irradiation sources are emission ends of the optical fibers.
According to another embodiment of the present invention, there is provided an imaging method for generating a change in a physical characteristic according to imaging data on an imaging medium by the above imaging apparatus.
According to another embodiment of the present invention, there is provided a printing apparatus for executing printing on a recording medium using an imaging medium imaged by the above imaging.
According to a favorable embodiment of the present invention, there is provided the printing apparatus wherein said imaging apparatus is provided in its interior, and an imaging operation is executed in its interior of the apparatus, thereafter the printing is executed using said imaging medium in its interior of the apparatus.
According to another embodiment of the present invention, there is provided an optical fiber array apparatus including: a plurality of optical fiber rows having emission ends of optical fibers arranged each other in a row with a predetermined pitch and an optical fiber support member for supporting said optical fiber rows, said optical fiber array apparatus comprising: parallel portions closely contacting said optical fiber rows along said optical fiber rows; and restricting portions for restricting movement of said optical fiber rows in their arranging direction so as to position said optical fibers such that a distance between optical axes of the optical fibers at the edge of each of said optical fiber rows in a projection direction forming a predetermined angle to said arranging direction is substantially a constant value.
According to another embodiment of the present invention, there is provided the optical fiber array apparatus wherein two or more parallel portions are provided at said optical fiber support member, and the restricting portions are provided at at least one edge of each of said parallel portions.
According to another embodiment of the present invention, there is provided the optical fiber array apparatus wherein said optical fiber support member comprises one or more optical fiber arranging members, support member of said arranging members, at least one parallel portion and at least one restricting portion are provided to said optical fiber arranging members.
According to another embodiment of the present invention, there is provided the optical fiber array apparatus further comprising at least one another optical fiber_row closely contacting the optical fiber row being closely in contact with said parallel portions, and having emission ends of optical fibers arranged each other in a row with a predetermined pitch;
According to a favorable embodiment of the present invention, there is provided the optical fiber array apparatus wherein at least one array of the optical fiber rows being closely in contact with said parallel portions and said another optical fiber row is formed in a barrel-piling manner.
According to another embodiment of the present invention, there is provided an optical fiber array apparatus including: a plurality of optical fiber double rows having a first optical fiber row having emission ends of optical fibers arranged each other in a row with a predetermined pitch and a second optical fiber row closely contacting said first optical fiber row and having emission ends of optical fibers arranged each other in a row with a predetermined pitch, said second optical fiber row arranged at a position shifted by 0.5 times as large as said predetermined pitch in said arranging direction from said first optical fiber row; and an optical fiber support member for supporting said optical fiber double rows, said optical fiber support member comprising: parallel portions closely contacting said first optical fiber rows along said first optical fiber rows; restricting portions for restricting movement of said optical fiber double rows in their arranging direction so as to position said optical fibers such that a distance between optical axes of the optical fibers at the edge of each of said optical fiber rows in a projection direction forming a predetermined angle to said arranging direction is substantially a constant value.
According to a favorable embodiment of the present invention, there is provided the optical fiber array apparatus wherein two or more parallel portions are provided at said optical fiber support member, and the restricting portions are provided at least one edge of each of said parallel portions.
According to a favorable embodiment of the present invention, there is provided the optical fiber array apparatus wherein said optical fiber support member comprises one or more optical fiber arranging members, support members of said arranging members, at least one parallel portion and at least one restricting portion are provided to said optical fiber arranging members.
According to a favorable embodiment of the present invention, there is provided an optical fiber array apparatus including: a plurality of optical fiber rows having emission ends of optical fibers arranged each other in a row with a predetermined pitch and an optical fiber support member for supporting said optical fiber rows, said optical fiber array apparatus comprising: pairs of parallel portions closely contacting each of both sides of said optical fiber rows along said optical fiber rows; and restricting portions for restricting movement of said optical fiber rows in their arranging direction so as to position said optical fibers such that a distance between optical axes of the optical fibers at the edge of each of said optical fiber rows in a projection direction forming a predetermined angle to said arranging direction is substantially a constant value.
According to another embodiment of the present invention, there is provided an imaging head apparatus comprising the optical fiber array apparatus and laser emission ends capable of supplying light to each of optical fibers in said optical fiber array apparatus, and an optical system for condensing laser beams emitted from said optical fiber array apparatus.
According to another embodiment of the present invention, there is provided an imaging apparatus for executing imaging by the above imaging head apparatus.
According to another embodiment of the present invention, there is provided an imaging apparatus for generating a physical change according to imaging data on an imaging medium using a plurality of beam irradiation sources which can be independently driven, said imaging apparatus comprising: a beam irradiation source control device for controlling said beam irradiation sources such that said beam irradiation sources are maintained to be an ON-state at an imaging operation time in an imaging area, an imaging data present portion is irradiated with energy beams having irradiation energy density larger than a sensitivity threshold value of an imaging medium, and an imaging data absent portion is irradiated with energy beams having irradiation energy density smaller than the sensitivity threshold value of the imaging medium; and sub-scanning control device for controlling a sub-scanning means or beam irradiation sources such that the closest lines in the main scanning direction are not imaged simultaneously at said imaging operation time.
According to another embodiment of the present invention, there is provided an imaging apparatus for generating a physical change according to imaging data on an imaging medium using a plurality of beam irradiation sources which can be independently driven, said imaging apparatus comprising: a beam irradiation source control device for controlling said beam irradiation sources
such that said beam irradiation sources are maintained to be an ON-state at an imaging operation time in an imaging area, an imaging data present portion is irradiated with energy beams having irradiation energy density being 1.5 to 2.5 times as large as a sensitivity threshold value of an imaging medium, and an imaging data absent portion is irradiated with energy beams having irradiation energy density corresponding to 70% to 90% of the sensitivity threshold value of the imaging medium.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein the beam irradiation sources are controlled to be turned on at a standby position out of the imaging area before starting said imaging operation, and an imaging head is controlled to be moved into the imaging area after a rotation speed of an imaging medium support drum reaches a stable rotation speed at the imaging operation time.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein an energy beam heat discharge member is provided at a position which is within a beam irradiation allowable portion of said beam irradiation sources at said standby position, and which is a position where the irradiation beam density is {fraction (1/10)} or less than irradiation energy density at a focal position.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein an imaging head is controlled to be moved into the imaging area before starting said imaging operation, and the beam irradiation sources are controlled to be turned on in the imaging area after a rotation speed of an imaging medium support drum reaches a stable rotation speed at the imaging operation time.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein said beam irradiation sources are emission ends of a laser device formed of a compound semiconductor.
According to a favorable embodiment of the present invention, there is provided the imaging apparatus wherein said beam irradiation sources are emission ends of the optical fibers.
According to another embodiment of the present invention, there is provided an imaging method for generating a change in a physical characteristic according to imaging data on an imaging medium by the above imaging apparatus.
According to another embodiment of the present invention, there is provided a printing apparatus for executing printing on a recording medium using an imaging medium imaged by the above imaging apparatus.
According to another embodiment of the present invention, there is provided the printing apparatus wherein said imaging apparatus is provided in its interior, and an imaging operation is executed in its interior of the apparatus, thereafter the printing is executed using said imaging medium in its interior of the apparatus.
According to another embodiment of the present invention, there is provided an imaging apparatus for generating a physical change according to imaging data on an imaging medium using beam irradiation sources, said imaging apparatus comprising: imaging medium support means; beam irradiation means for projecting energy beams modulated in accordance with imaging data onto the imaging medium attached to said imaging medium support means; and focal position adjusting means for adjusting the positional relationship between said beam irradiation means provided in said imaging medium support means in accordance with the position on said imaging medium and said imaging medium.
According to another embodiment of the present invention, there is provided an imaging apparatus for generating a physical change according to imaging data on an imaging medium using beam irradiation sources, said imaging apparatus comprising: imaging medium support means; beam irradiation means for projecting energy beams modulated in accordance with imaging data to the imaging medium attached to said imaging medium support means; a focal position detecting member, provided in said imaging medium support means in accordance with the position on said imaging medium, having an energy passage line where a passage state of said,energy beams changes in accordance with a focal state of said energy beams; a detector for measuring the energy beams passed through said focal position detecting member; and focal position adjusting means for adjusting the positional relationship between said beam irradiation means and said imaging medium.
According to another embodiment of the present invention, there is provided the imaging apparatus further comprising focal position controlling means for controlling an operation of said focal position adjusting means in accordance with an output value of said focal position detecting means.
According to a favorable embodiment of the present invention, there is provided the imaging apparatus, wherein said energy passage line is substantially a rectangular opening portion for passing energy, and the position of the sub-scanning direction of one of sides of said opening portion in the sub-scanning direction is set to a position substantially equal to the central axis of the energy beam at a focal position adjusting time.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein said energy passage line is substantially a circular opening portion for passing energy, and a diameter of said opening portion is 0.9 to 1.1 times as large as a beam diameter of the energy beam at the focal position.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein said energy passage line is periodically set in the main scanning direction.
According to a favorable embodiment of the present invention, there is provided the imaging apparatus wherein said detector has energy detecting elements divided in the sub-scanning direction in a state that a central axis of the energy beam is used as reference, and outputs of the energy beams being incident on the respective portions of said energy detecting elements are separately detectable.
According to another embodiment of the present invention, there is provided an imaging apparatus for generating a physical change according to imaging data on an imaging medium using beam irradiation sources, said imaging apparatus comprising: imaging medium support means; beam irradiation means for projecting energy beams modulated in accordance with imaging data to the imaging medium attached to said imaging medium support means; focal position detecting means moving with said beam irradiation means as one unit; and focal position adjusting means for adjusting the positional relationship between said beam irradiation means and said imaging medium.
According to a favorable embodiment of the present invention, there is provided the imaging apparatus wherein said focal position detecting means is a laser typed displacement sensor.
According to a favorable embodiment of the present invention, there is provided the imaging apparatus, wherein said focal position detecting means is an eddy current typed displacement sensor.
According to a favorable embodiment of the present invention, there is provided the imaging apparatus wherein said focal position detecting means is an electrostatic capacitance typed displacement sensor.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein said focal position adjusting means operates said beam irradiation means in a direction intersecting at right angles with both the main scanning direction and the sub-scanning direction with respect to said imaging medium fixed to the imaging medium support means so as to adjust the positional relationship between said beam irradiation means and said imaging medium.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein said focal position adjusting means is an X-stage with a micrometer.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein said focal position adjusting means is an X-stage driven by a stepping motor.
According to a favorable embodiment of the present invention, there is provided the imaging apparatus wherein said focal position adjusting means is an X-stage driven by a linear motor.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein said imaging medium support means is a drum.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein the plurality of said beam irradiation sources, which can be independently driven, are used.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein said beam irradiation sources are emission ends of a laser device formed of a compound semiconductor.
According to another embodiment of the present invention, there is provided the imaging apparatus wherein said beam irradiation sources are emission ends of the optical fiber.
According to another embodiment of the present invention, there is provided an imaging method for executing imaging by the above imaging apparatus.
According to another embodiment of the present invention, there is provided a printing apparatus for executing printing using an imaging medium imaged by the above imaging apparatus.
According to a favorable embodiment of the present invention, there is provided the printing apparatus wherein said imaging apparatus is provided in its interior, and an imaging operation is executed in its interior of the apparatus.
In the present invention, the imaging medium denotes a film or a plate having a multi-stage piling structure including a layer showing specific reactions to the irradiation of the beam irradiation sources such as laser beam sources. In many cases, the specific reactions are classified into a photon mode and a heat mode depending on the difference in the reaction.
In the case of the photon mode, in a layer showing the specific reaction, that is, a photosensitive layer, an imaging characteristic such as solubility to specific solvent is changed by optical energy of the beams. In other words, for example, a soluble property is changed to an insoluble property, or an insoluble property is changed to a soluble property. Also, there is a possibility that a change in light transmittance, and occurrence of an affinity for specific solution in the surface layer will be brought about. Then, a developing process using specific solvent is added after an imaging process, so that an original film or a press plate is formed.
In the case of the heat mode, the layer showing the specific reaction, that is, a heat sensitive layer is removed by heat energy of the beams, or the heat sensitive layer is likely to be removed. When the layer is not completely removed by only the beam irradiation, a physical post-process is added thereto, so that the layer is completely removed. Thus, physical projections and depressions are generated, and the press plate is formed.
The imaging medium is not limited to the press plate for printing and the original film. For example, the recording medium to be finally printed (e.g., photographic printing paper) may be used. Or, there may be used the photosensitive member such as an electrophotographic printer in which the image is once formed and transferred to the final recording medium. Also, the display elements may be used.
As the press plate for printing, as described in Unexamined Japanese Patent Publication No. 6-186750, there is favorably used the press plate comprising a substrate, a heat sensitive layer (or photosensitive layer) formed thereon, and a surface layer formed on the heat sensitive layer wherein the heat sensitive layer has a different affinity from the surface layer for printing liquid such as ink or liquid of ink repulsion (dampening water). Also, a primer layer is formed between the heat sensitive layer (photosensitive layer) and the substrate, and the difference in the affinity may be provided between the primer layer and the surface layer. As the heat sensitive layer for the heat mode, material in which carbon black is diffused to nitrocellulose, or the metal film such as titanium is favorably used.
Thus, in the specification of the present invention, the properties such as the shape, the chemical affinity, and optical properties such as light transmittance, which differs depending on the portion subjected to the beam irradiation or the portion subjected to non-beam irradiation, are referred to as imaging properties or physical properties of the imaging medium and the change in such properties is particularly referred to as a physical change.
In the present invention, the xe2x80x9cbeam irradiation sourcesxe2x80x9d include sources for generating a beam of light (including electromagnetic waves such as ultraviolet rays, visible radiation, infrared rays,) such as a laser beam, and a generation source of particle beams such as electron beams. Also, other than the beams having the define directivity, the following sources are included in the xe2x80x9cbeam irradiation sourcesxe2x80x9d of the present invention. Specifically, there are included all sources, which can resultingly cause the change in the imaging properties in the minute portion of the imaging medium by the discharge of such as a stylus electrode used in an electrostatic printer.
The most favorable beam irradiation sources are emission ends of optical fibers which are connected and coupled to the laser light sources or the emission ends of the light sources. To miniaturize the apparatus, a semiconductor laser is favorably used as the beam irradiation source. To obtain high power, a gas laser such as an argon ion laser, a carbon dioxide laser, or a solid laser such as a YAG laser is favorably used. Also, xe2x80x9cbeam irradiation meansxe2x80x9d denotes means including the beam irradiation sources and the optical system for projecting beam irradiation obtained from the beam irradiation sources to the imaging medium. Optical guides such as a reflector, a lens system, a rod lens system can be included other than the beam irradiation sources.
In the present invention, the xe2x80x9clinear stagexe2x80x9d indicates a xe2x80x9clinear motor typed linear stagexe2x80x9d or a xe2x80x9cball screw typed linear stage.xe2x80x9d The linear motor typed linear stage is a stage, which has no mechanical transmission mechanism, which needs play such as a gear, a ball screw in the intermediate portion between an actuator such as a motor and a moving object, in the movable stage. For example, in the linear motor, the movable stage is moved along the linear guide by a repulsion force and a suction force of a permanent magnet or an electromagnet, thereby reducing the generation of play. By such a driving principle, even when the intermittent driving is performed, the high positional accuracy can be obtained, and the moving distance can be dynamically varied. In other words, the moving distance can be relatively easily varied for each driving operation.
On the other hand, in the ball screw typed linear stage, the movable stage is connected through the mechanical transmission mechanism, which needs play, such as the ball screw and the gear rotatable in the linear guide. Then, the mechanism is rotated by a stepping motor so as to move the movable stage. In the ball screw typed linear stage, the positional shift easily occurs in the repetitive operation of stop and move such as the intermittent driving because of the property of the mechanical transmission mechanism for which play is indispensable. In many cases, the continuous driving of the ball screw typed linear stage is generally executed at a fixed speed. However, the ball screw typed linear stage has an advantageous in the point that the cost of the driving devices and the material is relatively low as compared with the linear motor typed linear stage, which needs the expensive driving devices due to the complicated driving system and the expensive material of the permanent magnet.
Demerits caused when the continuous driving of the linear stage is executed will be explained as follows. Specifically, when the imaging head is continuously moved in the direction of the rotation axis of the medium support drum at a fixed speed while continuously rotating the medium support drum at an uniform speed, there is a problem in which an image is diagonally formed with respect to a reference direction of the original imaging area of the imaging medium.
In other words, in the imaging apparatus 9 as shown in FIG. 59, it is assumed that the imaging medium 98 is rotated in a direction R (rotational direction of the medium support drum 91) at a circumferential speed Vx and the imaging head 92 is moved in a direction S (direction of the rotation axis of the medium support drum 91) at a feeding speed Vy. In this case, as shown in FIG. 60A, it would be ideal if imaging dots 102 formed in an imaging area 101 would be arranged along the direction of the imaging area 101 in a matrix form of a rectangle.
However, the imaging apparatus 9 scans the imaging head in the direction of the rotation axis as rotating the medium support drum. For this reason, the imaging medium 98 is fixed to the medium support drum 91 such that the reference direction of the imaging area becomes parallel to the rotation axis of the medium support drum 91. Also, the scanning direction of the imaging head completely conforms to the S direction (xcex4=0 in the figure). At this time, the imaging dots 102 are changed to be a parallelogram as shown in FIG. 60B.
Generally, in the imaging apparatus 9, the following method is used to prevent the image on the imaging medium 98 from being a parallelogram. More specifically, the feeding direction of the imaging head is inclined by xcex4 in advance in a state in which the central portion of the image allowable range of the imaging apparatus is set as a center and the rotation axis of the medium support drum 91 and the beam irradiation direction are set as axes. As a result, as shown in FIG. 60C, the image is formed to be inclined by xcex4 with respect to the reference direction of the original imaging area 101 of the imaging medium 98. If the linear motor typed linear stage, which is capable of intermittently driving, is used in the scanning of the imaging head 92, there occurs no problem in which the image is inclined.
In the specification of this invention, excepting for the case in which the discussion of the above problem is made, there is a case in which the direction of the rotation axis of the imaging medium support drum and the sub-scanning direction are not distinguished from each other, or regarded as substantially the same as each other for the sake of convenience even when such inclination xcex4 is present.
In the present invention, xe2x80x9cscanning meansxe2x80x9d denotes means for relatively moving the imaging medium and the directional position of the beam. The scanning using the rotation of the drum, and the scanning using beam deflecting means such as a polygon mirror are used as the scanning means other than the above-mentioned linear stage. Particularly, when the supporting means of the imaging medium is the drum, the rotation of the drum is preferably used as the main scanning means and the linear stage is preferably used as the sub-scanning means. When the supporting means is a flat bed member, the beam deflecting means other than the linear stage is preferably used as the main scanning means and the linear stage is mainly used as the sub-scanning means preferably.
In the present invention, the xe2x80x9cfeed amountxe2x80x9d means the distance where the stage moves after the imaging for one circumference is executed in the main scanning direction in the case of using the linear motor typed linear stage. Also, the xe2x80x9cfeed amountxe2x80x9d means the distance where the stage moves while one rotation of the medium support drum is performed in the case of using the ball screw typed stage.
In the specification of this invention, the portion of the imaging medium where the change of the imaging characteristic (physical change) should be generated is referred to as the imaging data present portion. The portion of the imaging medium where the change of the imaging characteristic (physical change) should not be generated is referred to as the imaging data absent portion. In many cases, the portion where the change in the imaging characteristic on the imaging medium is generated is formed as imaging dots on the final recording medium such as paper. Conversely, because of the difference in the affinity for liquid such as ink or liquid of ink repulsion of the imaging medium, there is a possibility that the portion where the change in the imaging characteristic on the imaging medium is not generated will be formed as imaging dots on the final recording medium.
In the present invention, xe2x80x9cfocal position detecting meansxe2x80x9d is means for detecting the distance between the imaging head including the beam irradiation sources and the imaging medium. Actually, the distance between the imaging medium or the imaging medium support member and the displacement sensor head is detected using the displacement sensor. Then, the distance between the imaging head and the imaging medium is calculated from the positional relationship among the displacement sensor, the imaging head and the imaging medium or the imaging medium support member.
As the distance measuring principle of the displacement sensor, there are used an optical system using the laser utilizing optical interference, beat etc., an eddy current system for detecting the change in the eddy current, an electrostatic capacitance type for detecting the change in the electrostatic capacitance are used. In addition, there is a system using an energy passage line to directly detect the focal state of the beams for imaging to be described later. The focal position detecting means may be combined with the beam irradiation sources for imaging, the imaging medium or the supporting means.
Any embodiment can be used as any one of focal position detecting means. In the case of the optical system, the eddy current system and the electrostatic capacitance system, the combination with the beam irradiation sources can be easily used. In the case of the system using the energy passage line, the combination with the imaging medium or the support means can be easily used in the transmission type, and the combination with the beam irradiation sources can be easily used in the reflection type.
In the present invention, the xe2x80x9cenergy passage linexe2x80x9d is that a part or all energy beams irradiated are transmitted or reflected. At this time, the magnitude, the direction, the phase of the transmitted energy or the reflected energy are changed, depending on a state that focus is achieved or a state that focus is not achieved. Specifically, there is provided an opening portion, and all energy beams are transmitted through the opening portion in the focal state. If the focus is shifted, the passage of the part of the energy beams is shifted from the opening portion, and the transmittance state of the energy beams is changed. Also, the lens and the reflecting mirror can be also used as the energy passage line. In this case, the magnitude and the direction of the energy beams to be transmitted or reflected are changed, depending on the focal state.